Updated 8th October 2006; 16th January, 10th May, 28th October, 18th December 2007; 16th April, 4th, 21st October, 9th November 2008; 7th, 16th May, 5th November 2009; 6th January, 14th May, 4th, 15th October 2011; 27th September 2012; 5th December 2015; 19th February 2016; 1st July, 24th September 2018; 15th September, 27th October 2019; 8th January 2020; 26th September 2024

When you're standing next to it, the cave has an obvious, draughting entrance that was pointed out to Matienzo cavers one Sunday afternoon by a Spaniard who'd remembered it from his childhood. The location was confirmed in 2018.

Each section should be given a proper description. The surveys next to the batches are png files produced from Tunnel (with no shown scale). This is (probably) a temporary measure until the descriptions of each section is written up (with references to some photos?!). The Easter 2006 draft 1 survey (with scale) can be seen here. The survey with the addition of the Easter 2008 extensions is a "work in progress". The survey will be updated (if possible) after trips in 2024 found the drawn survey incomplete and without names to tie in with the description. See Survey note below.

Entrance Series (survey - batch 2366_06_01 Carmen)
   The entrance lies at the top of a field, near a fence and is a crouch into taller, metre-wide passage. The ways soon split but by keeping to the left a pair of 3m drops are met. The first one is the easiest and drops into a short crawl to enlarging passage, 3 to 4m high. After some 60 or 70m the passage lowers over mud to a mud choke. A few metres back, a narrow 3m climb up (Rotter's Rift, marked by rock debris on the floor) enters a narrow phreatic rift that intersects a draughting rift parallel to the previous passage. Following the southern route, a narrow passage soon enters an enlargement with a number of passages going off. The first passage to the east reaches a choke after 20m where a bone has been found.
   All other routes to the east end up in a comparatively large chamber with large blocks climbing up to a choke. Underground hammering from this area was probably heard on the surface near a low arch 37m north of the Torno barn. It seems possible that this choke was an old entrance and possibly the route taken by the skull found in Skull Chamber (which is currently 2 hours away in a long loop, or much less through the tight Andy's Back Passage). With this possibility in mind, some digging has occurred in the Tigger Series (see below). The chamber area also has interesting mixed floor / wall deposits with alternating calcite and cobble sequences.

Easter 08 Series
   This starts a few metres back from Rotter's Rift as a climb into the roof. A complicated and generally small series that heads out to the west, parallelling the entrance hillside and ending up close to the valley that runs up to Barrio Regolfo. Surveying and digging out sections in nearly 1.1km of new passage provided several teams with a project over a number of days.
   Batch 08-05 From station 17 (near the formations in the main passage), a side passage continues straight ahead for about 15m until it becomes very small and splits into two. This point is very near to the Granny's Slippers area in the main cave. Just before the end an opening on the right appears to get a little larger ahead. At the start of the side-passage, a crawl on the left curves back towards the main passage before becoming very low.
   Batch 08-06 The passage continuing straight ahead at the junction is a mixture of flat-out crawling and hands-and-knees. After 45m it reaches a small chamber with a slope down into a tight passage, only suitable for very small people. On the left at the junction the passage soon turns right again until it runs parallel to the first passage. It ends after 25m at a small chamber and choke.
   Batch 08-07 From station 5 in the main passage, a calcite slope becomes too small after only 10m, although an audio connection could be made with the passage starting at station 11.
   Batches 08-08/09 From station 11 the passage slopes up, becomes a crawl and turns left. Straight ahead reaches the audio connection with the side-passage from station 5. The way on is to the right, along a crawl to a U-tube in the floor that was dug out. This rises to a tube ("Tom's Gambit") that continues tortuously round several sharp corners for about 45m, until it reaches another crawl that needed digging out. This breaks out into a much larger passage. On the right (heading East) it becomes a wide, walking-size tunnel 45m long, ending at a choke with a small hole down on the left with a slight draught. To the left (bearing West) two passages on the right-hand side meet in a high and narrow rift passage that heads north-east, divided up along its length by a number of flowstone "humps". At the top of the last flowstone slope, an aven can be seen through a small hole in the calcite. A lump hammer is needed to gain access to the aven and possibly the continuation of the rift. Straight ahead, at the end of the West Passage, a mud and boulder slope rises to a passage becoming too low, while on the left a sandy-floored rift is the start of "Endgame". (This end is also described in the 2008 autumn logbook, date 21/10/08.)

Description required for the following batches:
2366_08_02 Carmen Smith, Sarah Payne, Tom Chapman
2366_08_03 Carmen Smith, Dave Cooke (later addition from Patrick / Becka)
2366_08_10 "Torno - Endgame" Patrick Warren, Becka Lawson

Main route down to Axe Wars Inlet (survey - batch 2366_06_02 Carmen)
   The roped traverse is intersected by the short cut to Skull Chamber - see the account below. Andy's Back Passage goes off on the left just before the end of the roped traverse. On the opposite side is a passage (batch 2366_08_01 Bob Toogood, Dave Gledhill, Martin Barnicott) past a stal barrier into a small bedding chamber with the way on choked with mud. On a trip in 2008, the rope traverse in Meander Passage was bypassed (sketch) by dropping down a hole just before the start (to the left of the large block). This drops straight into the "major inlet" to the chamber, described below.

Continue down to near Torno Chamber (survey - batch 2366_06_03 Pete Smith)
   At the right-hand corner that marks the end of Mundy's Meanders, drop down to floor level. The rift soon turns to the left and slopes down to meet a stream passage. On the left, the upstream passage is Axe Wars Inlet. Downstream, scramble over a pile of boulders to a slightly larger passage where an inlet [No name?] enters on the right. Continuing downstream, after a further 20m another inlet, Where are the Numbers?, enters on the left. The main passage now continues for approximately 100m, with a cobble floor and some pools, and gradually reduces in height from stooping to crawling, until it reaches a point where it had to be dug out.

Major inlet passing under main route in. (survey - batch 2366_06_04 Sam)
   (Note: It is possible to climb up from the inlet to avoid the rope traverse - see "Main route down to Axe Wars Inlet", above.) Near the end of this batch, in the autumn of 2008, a body-sized tube on the right was noticed with visible passage beyond a removable constriction.

Tigger Series (survey - batch 2366_06_05 Ali)
   Tigger Series is entered opposite the large chamber near the surface. By heading away to the west from the main passage and keeping left, crawling leads past 2 faecal deposits to a tighter section and a crawl heading east and slightly uphill - the Kings Dig. This is, according to the 2006 survey, directly below Skull Chamber. Sand has been dug out but the going is now more difficult in clay. Bird bones have been found in these deposits. Digging at Easter 2007 was curtailed by possible "bad air".    The other digs just beyond this junction have yet to be attempted.
   The small chamber at the start of the Tigger Series had been molephone-positioned to the surface; photos can be seen here.

14m opposite Tigger Series (survey - batch 2366_06_06 Ali)
Description

Axe Wars Inlet (survey - batch 2366_06_07 Ali)
Description

High level extension downstream of Tigger Series (survey - batch 2366_06_08 Pete Eagan)
Description

Where Are the Numbers? & Dead Animals All Around (survey - batch 2366_06_09 Paul Dold?)
Description. A small number of sample fossils were removed for identification in December 2006 and can be seen here.

Axe Wars high level extensions (survey - batch 2366_06_10 Sam)
Description

Short link into Torno Chamber; Torno Chamber; 1st section of Rampant Rabbit inlet (survey  to be altered - batch 2366_06_11 Paul Dold?)
   There are 2 leads out of Torno Chamber, the lowest point is easily diggable and has a weak draught. The furthest northwest point has a strong draught exiting the chamber over a too-low crawl on mud. It would probably need 1 - 2 days work to clear to the furthest visible point (6m or so). Next to this on the left is the Lube Tube - best left alone. A climb up a giant sloping boulder leads to the Canyon Extension - see below.
   In December 2006, the bedding which takes water from an inlet in the roof was pushed through Toad Crawl to a sump which is about 1m wide, and half a metre high with 0.25m of soft silt on the floor. The main sink, where water disappears under rocks is a long term dig.
   Batch 2366_09_03 is the survey into the "sandy dig" at the bottom of Torno Chamber. This goes about 20m with a squeeze between rocks. There is a small "sit-up" chamber with a drop into over welly water. This has been pushed through 2" airspace into (unsurveyed?) passage. The sandy crawl continues for another 20m approximately and then a junction with a cobbled floor is seen with at least 3 ways on. A cold draught can be felt at this point and remains to be pushed. A visit at Easter 2011 made no progress. A visit in the summer 2011 found the area too wet to make any progress.

Rampant Rabbit (survey - batch 2366_06_12 Jim)
Description

Northern extension off Rampant Rabbit (survey - batch 2366_06_13 Paul Windle?)

The summer 2006 extensions (batches 06_14 to 06_20) have not been processed in Tunnel. The full survey, redrawn in Corel Draw after September 2006, can be seen here. Passage descriptions below have been lifted from the summer 2006 logbook.

Canyon Extension (NW of Torno Chamber) - batch 2366_06_14 Patrick Warren & Carmen Haskell
   A climb up a giant sloping boulder at the northern end of Torno Chamber enters a crawl over a pool and a short passage to a chamber. The left (right?) inlet (not shown on survey) is a horrible rift connected to the canyon below Windles Junction. The right (left?) inlet is a 3m climb and a short canyon to a chmaber and climb up mud to pop out into a very large NW-SE trending rift. Downstream (NW) leads to boulder falls. The apparent main way on is to the west but this is also boulder-choked - a small crawl at floor level is too tight. A climb up at the end of the big rift gains a large chamber with boulders. A phreatic passage leads off right but gets too small after about 30m.
Canyon Passage 08 Extension
   The Canyon Passage in the southwest sector of Cueva del Torno at Fresnedo was dug on a number of occasions and entry gained through the boulder choke in a low level crawl to open passage. The main route varies between 1.5 to 3.5m wide with roof approaching 20m above in places. The draughting route finishes in another dangerous boulder choke collapse, 50m from the Road to Torno in Cueva Riaño. An inlet near the end was bolted up during an 18 hour trip but the water emerged from a tiny hole. To prove the connection, a smoke test with molephones should be the way to go. In all, 667m were surveyed in this section of the cave, including 120m in a high level rift passage that heads south east from the initial boulder choke. In 2012, after another push for the Cueva Riaño link, it was thought a good idea to have people at both ends of the caves to aid the connection.
   In the summer of 2008, this latter passage was extended into a complicated series above Torno Chamber (batch 2366_08_16) (photo). The side passage goes through a thrutch up and through into a whole new network of draughting passages above the previously known system. The series starts with a couple of highly entertaining squeezes through calcite windows, leading into traverses in dry meandering rifts with a stream far below until a slope up to a complex junction is reached. The righthand passage is traversing at high level in tortuous rift passage. There must have been extensive amounts of false floor because at times it appeared to be around 2m below and at others around 15m. The route breaks out into a high rift chamber with a potential way on up a wall and under a large wedged boulder. The disto reveals this to continue up for at least 20m with tantalising glimpses of white helictite covered stals appearing from the blackness. A return with bolts and dynamic rope is required. The chamber is left via a wonderfully exposed climb up a wall of fallen blocks, emerging in a larger chamber with an excellent rock arch running the length of the area. This chamber also has a possible climb up into a black space beyond a series of worryingly perched blocks. Climbing would theoretically be easy – if you could rely on the blocks staying in situ. Descent (in a condition fit to leave the cave unaided) would be trickier, as all the holds sloped down and out. Across the chamber, half-way up the sheer wall, a passage leads off and round a bend. As this involves a climb up above the previous climb up, a slip would result in a good 10m + fall. The roof of the chamber has a tube inlet heading up from which there is a small but steady flow of water. The positioning of this chamber and the type of rock etc. gives a strong indication that this could well be the bottom of the inlet from site 2414, although this is as yet unproven.
   A 2m climb/step up and back from the junction leads to a dry canyon passage and scramble up over blocks into a marvellously decorated chamber. One wall is completely covered in flowstone. It may be possible to climb but would wreck some of it. This may lead into the same area as the first chamber/rift so this needs checking out before wreaking destruction in this part of the cave. The chamber ends at a very large boulder choke with no immediately obvious way on. At the junction again, a very bold climb / bridge up (10m) and to the left over some very loose looking slabs gains a higher series of passages. These are negotiated with squeezes through / step over / run along / climb up a series of passages and avens. One passage ended in an excellent chamber with the lower section covered in gypsum flowers and a dog-tooth crystal floor, which is very painful on the knees. Another passage ends in a climb up an ascending rift where progress is blocked by loose, perched blocks above. Yet another easy crawling passage leads to a draughting aven from which a good inward draught emits. The slabs at the bottom of this aven are covered in scratch marks and paw prints. It was obvious that some large animal (badger / fox?) has spent considerable effort trying to get up the aven. Other similar scratch marks can be found in other areas of this section, although no obvious sign of bones (other than a mouse and a caddis fly) or piles of shit. From the junction, a left turn along a rift which then turns left and descends sharply. Various twists and turns meet the passage leading up to the ‘complex’ junction. (See Eldon PC Newsletter).
   This area (2366_08_16) was re-visited in November 2015 and the logbook account of the trip can be found here.

2009 Extensions
    This inlet into the Canyon Passage is approximately 100m after passing through the boulder choke. Hands-and-knees (and lower) progression passes through occasional pools with 30cm of water. The walls and floor are predominantly mud and the draught is in. There are "woodlice-like" creatures in the water - completely white. Exploration stopped after 140-150m where the roof lowered to around 30cm and the passage widened to about 3 - 4m. It needs a thin and determined person in dry conditions to pursue this lead. (Batch 2366_09_01). A separate survey has been drawn out for this passage.
   While attempting a connection with Cueva Riaño this new area (batch 2366_09_02) was found. Unfortunately, this was an inlet heading away from Riaño. A descending rift passage over blocks leads to a floor leads to a crsytal-covered floor with a shallow pool. A squeeze round a block enters the continuation of the rift with predominant stal and straw decoration. The rift forks and the right is blocked by excellent flowstone decoration. The left hand branch is also heavily decorated but it is possible to climb up through and beyond to a mass of loose boulders and false floors. There is no apparent way on. From the log: "Returned to chamber which appears to have been visited previously but not surveyed. Very, very loose and not pleasant at all. Several squeezes led to terminal chamberwith hanging death everywhere. I am not returning. No obvious way on at present." Drawn survey of batch.
On a trip to the end on 11th August 2019 (after some work in Cueva de Riaño), "all of the climbs / digs / chokes, etc" were re-checked and "nothing seemed very promising". It took 130 minutes to get out from the end. Photos can be seen here and video here.

Full description required for batches:
2366_08_04 Dan Hibberts, Johnny Latimer, Bill Sherrington, Bob Toogood
2366_08_11 Martin Barnicott, Bob Toogood (SE from boulder choke)
2366_08_12 Mike Salt, Dan Hibberts, Bob Toogood (high level back)
2366_08_13 Mike Salt, Dan Hibberts (Road to Riano - last section)
2366_08_14 Martin Barnicott +? (start of handline - traverse line??)
2366_08_15 Martin Barnicott Dave Gledhill (Passage in Gallery left of climb up into Posture of Progression)

Up to Granny's Slippers - batch 2366_06_15 Ali Neill
The passage leading to Granny's Slippers starts with fine formations including large, ancient gours on the left. (Passage behind gours links with route in). The passage continues under "organ pipes" and an inlet on the right (batch 06_17 below). The passage ends at a small stal blockage with no draught. However, holes in the right hand wall give access to a parallel passage. At a junction left looking out leads to a crawl and bend to the right. This pops out into a much larger chamber with fine formations. On the original exploration progress was stopped by a pit in the floor with the route continuing beyond.
At Easter 2007, a higher level passage was entered near station 2366_06_15.8. This series went for 127m , climbing almost up to entrance altitude. (Batch 2366_07_03 - Dan Hibberts, Jim Lister, Bob Toogood, Dave Gledhill and Martin Barnicott) . A description is required.

Rampant Rabbit Inlet - batch 2366_06_16 Patrick Warren & Carmen Haskell
   A 3m climb off Rampant Rabbit gains the inlet which rises up to a choke over RR. At the highest point the passage has broken into a chamber in the next bed of limestone up with many fine straws. Climbs of 3 and 4m enter a phreatic tube maze with a loop back.

Side Passage before Granny's Slippers - batch 2366_06_17 Patrick Warren & Carmen Haskell
   This side passage starts as walking but reduces to hands and knees before choking.

Granny's Slippers to "egg shells" - batch 2366_06_18 Patrick Warren, Paul Fretwell

Posture of Progression to Granny's Head + Hysteria 69 - batch 2366_06_19 Ali Neill Pete Eagan
    A traverse around the pit at Granny's Slippers enters a dry mud-floored passage. Around a left hand bend a difficult climb up (now laddered as a p6) leads to the Posture of Progression, mainly large, sandy, walking passage with an area of stals and curtains. The first junction on the right hand side is Hysteria 69 which leads back to the start of the passage.
   To the right, at a major junction, a way under boulders leads to a stal grotto and a short climb down which divides and becomes too narrow in both directions. On the right hand side an undescended pitch of 5m is followed after right angle bends by another undescended pitch of 6m. Opposite the last pitch is a tight traverse and climb down to enter an area of black washed limestone with a narrow slot in the floor which appears to open up below.
   Left at the major junction enters easy walking passage past stals and curtains. At an obvious stal. boss Andy's Back Passage (Batch 2366_07_01) is a small opening on the left which leads to a tight S-bend that has been enlarged. Past this, a climb down quickly gains two possible ways on. Straight ahead passes through two small bouldery chambers and at the back of the second, a hole in the rear wall leads to a short maze of passages that contains some interesting fossils but all passages here appear to end in mud digs or are too tight. At the initial climbdown a slope down to the right leads soon gains a small drippy chamber with a narrow rift exiting containing a good draught. Both this rift and the initial tight S-bend were dug at Easter 2007 to make a connection with the roped traverse earlier in the cave and this now provides a much quicker route to the area near Skull Chamber. (It was by this (new) route that the archeologist was escorted into the cave and the skull successfully removed).
   Two other side passages near the major junction appear to be choked with mud.
   In this area there are a number of (animal) bones and, at a corner above the Tigger Series, a human skull was found in August 2006 lying on mud. Nearby there are other bones and a metal artefact in a pit.
   The skull was taped off and then removed in April 2007 for study by Pedro Rasines, the specialist in human remains at the Altamira Museum. Initial cleaning of the skull brought to light that the person had sustained a substantial head injury with bone damage that appeared to partially heal over. (Photos and line drawings of the cranium by Jesús Ruiz Cobo are here). A station close to the skull was molephone-positioned at Easter 2007 and the surface above pock-marked with digs in the vacinity. Hand-held radio contact was made as well as hammering and shouting. (Photos of the molephoning can be seen here).
   The discovery of the skull started the hunt for another entrance and the opening up of Pig Nut Cave (site 2523) - which has its own remains (including bear) - and the dig in the streambed (site 2522). The Kings' Dig in the Tigger Series was also started (see above).
   A major article in volume 16 of Studies in Speleology - Heads Will Roll: Prehistoric human remains and pottery from two sites in the Matienzo area (North Spain) (Smith P, Corrin J and Ruiz Cobo J, 2008) describes the cranium and other bones found. The remains have been dated to the Bronze Age because of the method of burial: just inside a small cave entrance which is covered over. This method is common in the area and has been associated with pottery and artefacts which have been dated in other caves. Examples of similar burials include those in sites 709 and 565.
   Reference Ruiz Cobo Jesús and Muñoz Fernández Emilio et al, 2009 has a photo and describes the find. Ruiz Cobo Jesús et al, 2008a is a well-illustrated, major article describing the skull and the injury with possible causes. etc. The article can be read here.
   In 2009, a sand-filled tube in the Posture of Progression was dug over a couple of trips and about 8m of progress was made.

Western end of PoP to pit - batch 2366_06_20 Patrick Warren, Paul Fretwell

Survey
   The survey is due for another total redraw (ie version 3) after Easter 2007 when 2 molephone points were fixed. Certain passages have now moved 6 or 7m. The current survey is shown here (without batches 2366_07_01, _02 and _03 and the 2008 Easter extensions). The current survex file is shown here. As a temporary measure, scans are available of batches 07_01 and 07_03.

Miscellaneous
   In 2008, a fossil was removed and identified as a Liostrea Oyster from the Cretaceous. During a trip at Easter 2009, a connection down to "Ali25" in "eggshells" was made. A new chamber with fossils was found.
   Reference Smith P et al, 2015 has a summary of the archaeological work carried out within 2004 - 2016.

Link to entry in the Cave Diving Sump Index.

References: anon., 2006b (Easter logbook); anon., 2006d (summer logbook); anon., 2006e (autumn logbook); anon., 2006f (Christmas logbook); Corrin Juan, 2007 (survey and photos); anon., 2007b (Easter logbook); Corrin Juan and Smith Peter, 2007 (photos and survey); Corrin Juan, 2007a; anon., 2008c (Easter logbook); anon., 2008e (summer logbook); anon., 2008f (autumn logbook); Corrin Juan, 2009; Smith P, Corrin J and Ruiz Cobo J, 2008 (survey and drawings); anon., 2009a (Easter logbook); Ruiz Cobo Jesús et al, 2008a (survey and photos); Ruiz Cobo Jesús and Muñoz Fernández Emilio et al, 2009 (photo); anon., 2009c (summer logbook); Corrin Juan, 2010; León García José, 2010 (Volume 1 and Volume 2) (survey and photos); anon., 2011b (Easter logbook); anon., 2011d (summer logbook); anon., 2012d (summer logbook); Ruiz Cobo J and Muñoz Fernández E, 2013; Corrin Juan, 2013a; Papard Philip, Corrin Juan and Smith Peter, 2014; anon., 2015d (autumn logbook); Smith P et al, 2015; anon., 2018c (summer logbook); anon., 2019d (summer logbook); anon., 2024d (summer logbook)
Entrance pictures : 2006, 2007, 2018 : 2024
Underground pictures:
From 2024 reconaissance
The far south, August 2019
Entrance chamber, 2018 : Torno Chamber dig, 2011 : Spanish blog with photo, Sept 2011
2009 summer photos : Chamber with fossils, Easter 2009
82 pictures from Easter 2006 :  77 pictures from summer 2006 : 14 pictures in the entrance series, Xmas 2006  
12 pictures from Skull Chamber and fossils from Dead Animals...  
Pictures from Easter 2007: Molephoning (surface and underground); skull removal; others
Archaeology: Pictures of the cleaned-up skull
Video: (by Carmen Haskell) Steve Martin in tight section prior to enlargement
(by Juan Corrin)  Video sequence of selected 2006 photos. (20Mb)
Searching for a link through to Cueva Riaño, August 2019 (YouTube)
Detailed Survey : 1.5Mb png file produced in Tunnel - from Easter 2006.  End of 2006 (pdf file) : completed survey (2024) in hand
Line Survey :
On area survey :
Survex file : download (2009 summer) (Amended magnetic declination December 2013 to align with Eur79 grid and coordinates altered to fit ETRS89 datum, April 2014.)
shown with Fresnedo and 4 Valleys caves (now) (Coordinates altered to fit ETRS89 datum, April 2014.)
Passage direction rose diagram: 1/7/2018